The bobweight ain't an issue in your case (wont affect smoothness) unless you want/need the new pistons to weigh close enough to the OE ones so that you do not have to rebalance & you do have some leeway there (HF has a cheap digital scale on sale regularly for $10) I would suggest the cheapest rebuild kit you can find (with a few add ons) (pistons/pins/plasma file fit rings/rod/main bearings/cam bearings (maybe)/cam/lifters/gaskets/thin composition head gaskets. tweak the carb/dist after you get it running. read "breakin secrets" at www.mototuneusa.com it'd definitely be a plus if you could bump the SCR with some closed chamber heads or expensive pistons